Electrolytic extraction of dysprosium and thermodynamic evaluation of Cu-Dy intermetallic compound in eutectic LiCl-KCl

A label-free fluorescent peptide probe for sensitive and selective determination of copper and sulfide ions in aqueous systems

A label free fluorescent peptide probe (HDSGWEVHH) was used for Cu2+ and S2- determination in aqueous solution. Our results demonstrated that HDSGWEVHH is highly selective and sensitive for monitoring free Cu2+ concentration via quenching of the probe fluorescence upon Cu2+ binding. The mechanism of the complexation is investigated with Cyclic Voltammetry (CV), 1H nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR) spectroscopy and computational techniques. Theoretical calculation results indicated the binding ratio of the probe to Cu2+ is 2 : 1 and the binding constant was obtained as 1.72 × 10 8 M-1. Cu2+ concentration can be detected with the detection limit of 16 nM. Free Cu2+ concentration released from the metallothionein-Cu complex at different pH values was detected. Cu2+ concentration in real water and tea samples was also detected, and the results were consistent with the ones monitored by atomic absorption spectrometer. Because of the exceedingly small K sp value of CuS (1.27 × 10-36), S2- can sequester Cu2+ from HDSGWEVHH to restore the tryptophan (W) fluorescence. Thus the HDSGWEVHH-Cu2+ complex can also be used for S2- detection. The S2- concentrations can be monitored with a detection limit of 19 nM. The assay is also amenable to measurement of S2- concentration in pure water samples. Thus the probe designed herein is sensitive, label free, low cost, and environmentally friendly for Cu2+ and S2- determination in aqueous solutions.

Electrochemical properties of yttrium on W and Pb electrodes in LiCl-KCl eutectic melts

Cyclic voltammetry, square wave voltammetry, linear polarization, chronopotentiometry and chronoamperometry were performed to investigate the electrochemical properties of Y(iii) on W and Pb electrodes in LiCl–KCl eutectic melts. The diffusion coefficient of Y(iii) measured by various techniques was in the order of 10⁻⁵. The nucleation of Y on W electrode was found to comply with the instantaneous nucleation mechanism. With increasing temperature, the exchange current densities increased and the charge-transfer resistances decreased, and exchange current densities are distinctly larger on liquid Pb electrode compared with W electrode. In addition, the co-deposition mechanism of Y(iii) and Pb(ii) on W electrode was also studied and four Pb–Y intermetallics could be detected. The feasibility of extraction metallic Y from the melts was explored by co-deposition on W electrode and under-potential deposition on liquid Pb electrode and the extracted products consisted of Pb₃Y and Pb phases.

Cyclic voltammetry, square wave voltammetry, linear polarization, chronopotentiometry and chronoamperometry were performed to investigate the electrochemical properties of Y(iii) on W and Pb electrodes in LiCl–KCl eutectic melts.